Mobile communication system, radio base station containing control device in the mobile communication system and control method thereof

ABSTRACT

A mobile communication system includes: a mobile terminal unit (UE); a radio base station (Node B) for performing communication with the mobile terminal unit via radio line; a radio controller (RNC) controlling the radio base station and physically divided to first control means (CPE) for performing signaling transfer control and second control means (UPE) for accommodating a radio base station thereunder and performing user data transfer control; and a radio base station replacement control apparatus ( 51 ) for governing control of replacement of the radio base station. Since the radio base station replacement control apparatus ( 51 ) is separately arranged in a network (RAN), a specific CPE or a terminal resource control section need not have the control function of replacement of the radio base station, and accordingly control of the replacement of the radio base station can be concentratedly performed by this radio base station replacement control apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mobile communication system and aradio base station replacement control apparatus and control method and,more particularly, to a W-CDMA cellular type mobile communication systemand a radio base station replacement control apparatus and controlmethod.

2. Description of the Related Art

FIG. 1 shows the existing architecture of a W-CDMA communication systemas a mobile communication system. A radio access network (RAN) 1includes radio controllers (RNCs) 4 and 5 and Node Bs 6 to 9, and isconnected to a core network (CN) 3 as an exchange network via an Iuinterface. The Node Bs 6 to 9 mean logical nodes which perform radiotransmission and reception, and more specifically are radio base stationapparatuses.

The interface between the Node B and the RNC is called Iub, and an Iurinterface is also defined as the interface between the RNCs. Each Node Bcovers one or a plurality of cells 10, and is connected to a mobileterminal unit (UE) 2 via a radio interface. The Node B terminates aradio channel, and the RNC manages the Node Bs and selects andsynthesizes a radio path upon soft handover. Note that details of thearchitecture shown in FIG. 1 are defined by 3GPP (3rd GenerationPartnership Projects), and disclosed in non-patent reference 1.

FIG. 2 shows the protocol architecture of the radio interface in thisW-CDMA communication system shown in FIG. 1. As shown in FIG. 2, thisprotocol architecture includes three protocol layers, i.e., a physicallayer (PHY) 11 indicated by L1, data link layers 12 to 14 indicated byL2, and a network layer (RRC: Radio Resource Control) 15 indicated by L3(“W-CDMA Mobile Communication System”, edited by Keiji Tatekawa,published in 2001 by Maruzen, pp. 96 and 97).

Data link layer L2 is divided into three sublayers, i.e., a MAC (MediaAccess Control) layer 12, RLC (Radio Link Control) layer 13, and BMC(Broadcast/Multicast Control) layer 14. The MAC layer 12 has MAC-c/sh(common/share) 121 and MAC-d (dedicated) 122, and the RLC layer 13 has aplurality of RLCs 131 to 134.

Each ellipse shown in FIG. 2 indicates a service access point (SAP)between layers or sublayers, and the SAP between the RLC sublayer 13 andMAC sublayer 12 provides a logic channel. That is, this logic channel isprovided from the MAC sublayer 12 to the RLC sublayer 13, classified bythe functions or logical characteristics of transmission signals, andcharacterized by the contents of information to be transferred. Examplesof the logic channel are CCCH (Common Control Channel), PCCH (PagingControl Channel), BCCH (Broadcast Control Channel), and CTCH (CommonTraffic Channel).

The SAP between the MAC sublayer 12 and physical layer 11 provides atransport channel. That is, this transport channel is provided from thephysical layer 11 to the MAC sublayer 12, classified by transmissionforms, and characterized by the type of information and the way theinformation is transferred via the radio interface. Examples of thetransport channel are PCH (Paging Channel), DCH (Dedicated Channel), BCH(Broadcast Channel), and FACH (Forward Access Channel).

The physical layer 11 and the sublayers 12 to 14 of the data link layerare controlled by the network layer (RRC) 15 via C-SAPs which providecontrol channels. Details of this protocol architecture shown in FIG. 2are defined in TR25. 925 of 3GPP.

In addition, although not particularly shown in FIG. 2, a C (Control)plane for signaling which transfers control signals and a U (User) planewhich transfers user data exist, and the BMC sublayer 14 of L2 isapplied only to the U plane.

FIG. 3 is a block diagram showing an example of an open RAN architecturemade up of the RNCs 5 and 6 and Node Bs 6 to 8 shown in FIG. 1. As shownin FIG. 3, this example comprises a terminal position detector 101 whichcollects and calculates the positions of terminals, a common radioresource manager 102 which manages the radio access network environmentand optimizes the network load, a paging/broadcast network element 103which controls the flows of radio broadcast/multicast and notifies thestates of radio broadcast/multicast, a cell controller 104 whichcontrols permission, congestion, and allocation of radio access to eachradio base station apparatus, a mobile controller 105 which establishesand releases a transmission channel, a cell transmission gateway 107which transmits individual radio channel signals and performmultiplexing/separation of a common radio channel signal, a user radiogateway 108 which encrypts and decrypts a radio channel and controlscompression, multiplexing/separation, and retransmission of a header,and a radio layer 106 which generates position information of aterminal, encodes and decodes a radio channel, or controls the electricpower of a radio channel.

In this arrangement, the cell controller 104 controls radio access toeach radio base station apparatus, so control signals for controllingradio access are exchanged between the cell controller 104, celltransmission gateway 107, and radio layer 106 (e.g., Mobile WirelessInternet Forum (MWIF) “Open RAN Architecture in 3rd Generation MobileSystems Technical Report MTR-007” v 1.0.0 (Jun. 12, 2001)).

In the RNCs 4 and 5 of the radio access network (RAN) 1 as describedabove, a function of controlling the C plane and a function ofcontrolling the U plane are physically integrated. In this mobilecommunication system having the RNC in which these two control functionsof the U plane and C plane are integrated, when the signaling throughputis to be increased, an RNC itself must be added although it is onlynecessary to add the C plane control function, and, when the user datatransfer rate is to be increased, an RNC itself must be added althoughit is only necessary to add the U plane control function. Accordingly,it is difficult for the conventional RNC configuration to construct asystem having high scalability.

Also, the following problem arises upon soft handover. That is, when anormal call is set, one radio channel (radio link) is connected betweenthe RNC and Node B. However, when the UE (mobile terminal unit) moves tocause soft handover, two or more paths are connected between the RNC anda plurality of Node Bs. If soft handover occurs across the RNCs, a pathis connected by using the interface called Iur (FIG. 1) between aserving RNC and drift RNC.

If soft handover thus occurs across the RNCs, although a user data pathcan be connected from one U plane control functional unit to a pluralityof Node Bs in the soft handover state, a path for this purpose must beconnected between a serving RNC and drift RNC. This not only wastes theresources, but also produces a delay because data is transferred via theRNC. Therefore, a technique which separates the U plane control functionand C plane control function is possible. When the U plane controlfunction and C plane control function are to be separated in the systemshown in FIG. 3, the C plane control function can be formed by theterminal position detector 101, common radio resource manager 102,paging/broadcast network element 103, cell controller 104, and mobilecontroller 105, and the U plane control function can be formed by theradio layer 106, cell transmission gateway 106, and user radio gateway107.

In the arrangement shown in FIG. 3, however, the cell controllercontrols radio access to each radio base station apparatus, therebyexchanging control signals for controlling radio access between the cellcontroller, cell transmission gateway, and radio layer. Therefore, ifthe C plane control function is formed by the terminal positiondetector, common radio resource manager, paging/broadcast networkelement, cell controller, and mobile controller and the U plane controlfunction is formed by the radio layer, cell transmission gateway, anduser radio gateway, large amounts of signals for controlling radioaccess are exchanged between the portions implementing the C planecontrol function and the portions implementing the U plane controlfunction, and this complicates the control.

Also, when this configuration is applied to mobile communication systemshaving different radio schemes, the portions implementing the C planecontrol function and the portions implementing the U plane controlfunction must be formed in accordance with the number of the radioschemes. This increases the scale and cost.

Furthermore, when a system having high scalability can be constructed byseparating the C plane control function and U plane control function,for example, if a certain U plane control functional unit has failed oris overloaded, the accommodation of cells of a Node B under its controlcan be replaced to another U plane control functional unit. In thiscase, a certain specific one of a plurality C plane control functionalunits must representatively control this Node B cell replacement.Accordingly, this specific C plane control functional unit alone must begiven the Node B cell replacement control function. This makes itimpossible to form a configuration in which all C plane controlfunctional units have the same function.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the variousproblems of the above described related art, and has as its object toprovide a mobile communication system and a radio base stationreplacement control apparatus and control method which can construct asystem having high scalability, waste no resources, and produce nodelay.

It is another object of the present invention to provide a mobilecommunication system and a radio base station replacement controlapparatus and control method which can construct a system having highscalability, reduce the complexity of signal exchange control betweenapparatuses, and do not increase the scale more than necessary even whenradio schemes are different.

It is still another object of the present invention to provide a mobilecommunication system and a radio base station replacement controlapparatus and control method by which when a C plane control functionand U plane control function are separated, all C plane controlfunctional units can have the same arrangement.

In order to achieve the above object, according to a first aspect of thepresent invention, there is provided a mobile communication systemcomprising a mobile terminal unit, a radio base station whichcommunicates with said mobile terminal unit via a radio channel, and aradio controller which controls said radio base station, and isphysically separated into first control means for controlling transferof signaling and second control means for accommodating said radio basestation under the control and controlling transfer of user data,characterized by further comprising a radio base station replacementcontrol apparatus which controls replacement of said radio base station.

According to a second aspect of the present invention, there is provideda mobile communication system comprising a mobile terminal unit, a radiobase station which communicates with said mobile terminal unit via aradio channel, and a radio controller which controls said radio basestation, and is physically separated into first control means forperforming control independent of a radio transmission scheme and secondcontrol means for accommodating said radio base station under thecontrol and performing control depending on a radio transmission scheme,characterized by further comprising a radio base station replacementcontrol apparatus which controls replacement of said radio base station.

According to a third aspect of the present invention, there is provideda mobile communication system comprising a mobile terminal unit, a radiobase station which communicates with said mobile terminal unit via aradio channel, and a radio controller which controls said radio basestation, and is physically separated into first control means forcontrolling transfer of signaling and second control means foraccommodating said radio base station under the control and controllingtransfer of user data, said second control means performing controldepending on a radio transmission scheme, characterized by furthercomprising a radio base station replacement control apparatus whichcontrols replacement of said radio base station.

According to a fourth aspect of the present invention, there is provideda mobile communication system comprising a mobile terminal unit, a radiobase station which communicates with said mobile terminal unit via aradio channel, and a radio controller which controls said radio basestation, and is physically separated into first control means forcontrolling a terminal resource of said mobile terminal unit and secondcontrol means for accommodating said radio base station under thecontrol and controlling a base station resource of said radio basestation, characterized by further comprising a radio base stationreplacement control apparatus which controls replacement of said radiobase station.

According to a fifth aspect of the present invention, there is provideda mobile communication system as set forth in any one of the first tofourth aspects, characterized by further comprising a network whichconnects said first control means, second control means, and radio basestation replacement control apparatus.

According to a sixth aspect of the present invention, there is provideda mobile communication system as set forth in any one of the first tofifth aspects, characterized in that said radio base station replacementcontrol apparatus comprises means for notifying, in response to anexternal trigger, a radio base station as an object of replacement ofidentification information of second control means which is to newlyaccommodate said radio base station.

According to a second aspect of the present invention, there is provideda mobile communication system as set forth in the sixth aspect,characterized in that said radio base station replacement controlapparatus further comprises means for notifying said first control meansof identification information of said radio base station as an object ofreplacement and identification information of said second control meansas an accommodation destination.

According to a eighth aspect of the present invention, there is provideda radio base station replacement control apparatus which controlsreplacement of a radio base station in a mobile communication systemcomprising a mobile terminal unit, said radio base station whichcommunicates with said mobile terminal unit via a radio channel, and aradio controller which controls said radio base station, and isphysically separated into first control means for controlling transferof signaling and second control means for accommodating said radio basestation under the control and controlling transfer of user data,characterized in that said first and second control means are physicallyindependent of each other.

According to a ninth aspect of the present invention, there is provideda radio base station replacement control apparatus which controlsreplacement of a radio base station in a mobile communication systemcomprising a mobile terminal unit, said radio base station whichcommunicates with said mobile terminal unit via a radio channel, and aradio controller which controls said radio base station, and isphysically separated into first control means for performing controlindependent of a radio transmission scheme and second control means foraccommodating said radio base station under the control and performingcontrol depending on a radio transmission scheme, characterized in thatsaid first and second control means are physically independent of eachother.

According to a tenth aspect of the present invention, there is provideda radio base station replacement control apparatus which controlsreplacement of a radio base station in a mobile communication systemcomprising a mobile terminal unit, said radio base station whichcommunicates with said mobile terminal unit via a radio channel, and aradio controller which controls said radio base station, and isphysically separated into first control means for controlling transferof signaling and second control means for accommodating said radio basestation under the control and controlling transfer of user data, saidsecond control means performing control depending on a radiotransmission scheme, characterized in that said first and second controlmeans are physically independent of each other.

According to a 11th aspect of the present invention, there is provided aradio base station replacement control apparatus which controlsreplacement of a radio base station in a mobile communication systemcomprising a mobile terminal unit, said radio base station whichcommunicates with said mobile terminal unit via a radio channel, and aradio controller which controls said radio base station, and isphysically separated into first control means for controlling a terminalresource of said mobile terminal unit and second control means foraccommodating said radio base station under the control and controllinga base station resource of said radio base station, characterized inthat said first and second control means are physically independent ofeach other.

According to an 12^(th) aspect of the present invention, there isprovided a radio base station replacement control apparatus as set forthin any one of the eighth to 11^(th) aspects, characterized in that saidfirst and second control means are connected across a network.

According to a 13^(th) aspect of the present invention, there isprovided a radio base station replacement control apparatus as set forthin any one of the eighth to 12^(th) aspects, characterized by furthercomprising means for notifying, in response to an external trigger, aradio base station as an object of replacement of identificationinformation of second control means which is to newly accommodate saidradio base station.

According to a 14^(th) aspect of the present invention, there isprovided a radio base station replacement control apparatus as set forthin the 13^(th) aspect, characterized by further comprising means fornotifying said first control means of identification information of saidradio base station as an object of replacement and identificationinformation of said second control means as an accommodationdestination.

According to a 15^(th) aspect of the present invention, there isprovided a radio base station replacement control method in acommunication system comprising a mobile terminal unit, a radio basestation which communicates with the mobile terminal unit via a radiochannel, a radio controller which controls the radio base station, andis physically separated into first control means for controllingtransfer of signaling and second control means for accommodating theradio base station under the control and controlling transfer of userdata, and a radio base station replacement control apparatus which isprovided physically independently of the first and second control meansand controls replacement of the radio base station, characterized bycomprising the step of notifying, in response to an external trigger, aradio base station as an object of replacement of identificationinformation of second control means which is to newly accommodate theradio base station.

According to a 16^(th) aspect of the present invention, there isprovided a radio base station replacement control method as set forth inthe 15^(th) aspect, characterized by further comprising the step ofnotifying the first control means of identification information of theradio base station as an object of replacement and identificationinformation of the second control means as an accommodation destination.

According to a 17^(th) aspect of the present invention, there isprovided a program for causing a computer to execute a radio basestation replacement control method in a communication system comprisinga mobile terminal unit, a radio base station which communicates with themobile terminal unit via a radio channel, a radio controller whichcontrols the radio base station, and is physically separated into firstcontrol means for controlling transfer of signaling and second controlmeans for accommodating the radio base station under the control andcontrolling transfer of user data, and a radio base station replacementcontrol apparatus which is provided physically independently of thefirst and second control means and controls replacement of the radiobase station, characterized by comprising the step of notifying, inresponse to an external trigger, a radio base station as an object ofaccommodation of identification information of second control meanswhich is to newly accommodate the radio base station.

According to an 18^(th) aspect of the present invention, there isprovided a program as set forth in the 17^(th) aspect, characterized byfurther comprising the step of notifying the first control means ofidentification information of the radio base station as an object ofreplacement and identification information of the second control meansas an accommodation destination.

In the present invention as described above, a monitor controller isadditionally placed in the network. Therefore, even in a systemconfiguration in which a plurality of CPEs or a plurality of terminalresource control units are arranged in the network, the monitorcontroller can concentrically control the change of cell setting (therearrangement of Node Bs). This makes it unnecessary to give anyspecific CPE or terminal resource control unit the function ofcontrolling the change of cell setting (the rearrangement of Node Bs),and achieves the effect of giving the same arrangement to all CPEs orterminal resource control units. This is advantageous in respect of bothmanufacture and cost.

The above and many other objects, aspects, and advantages of the presentinvention will be apparent to those skilled in the art from thefollowing description and the accompanying drawings in which severalpreferred embodiments matching the principle of the present inventionare presented as the best mode for carrying out the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the existing system architecture using a W-CDMAcommunication method;

FIG. 2 is a view showing the system architecture shown in FIG. 1 as aprotocol architecture;

FIG. 3 is a view showing the system architecture shown in FIG. 1 as anopen architecture;

FIG. 4 is a block diagram showing an example of the protocolarchitecture of an RNC as the basis of an embodiment of the presentinvention;

FIG. 5 is a network diagram for explaining the ease of Node Breplacement by the arrangement shown in FIG. 4;

FIG. 6 is a view for explaining the state of soft handover when thearrangement shown in FIG. 4 is used;

FIG. 7 is a path connection sequence diagram when soft handover occursin the arrangement shown in FIG. 6;

FIG. 8 is a view showing the network configuration of an IP network whenthe arrangement shown in FIG. 4 is used;

FIG. 9 is a sequence diagram when radio links are to be simultaneouslyset for a plurality of Node Bs when the arrangement shown in FIG. 4 isused;

FIG. 10 is a sequence diagram when a radio link is to be additionallyset for a new Node B when the arrangement shown in FIG. 4 is used;

FIG. 11 is a block diagram showing an example of an open RANarchitecture as the basis of another embodiment of the presentinvention;

FIG. 12 is a network diagram for explaining the ease of Node Breplacement by the arrangement shown in FIG. 11;

FIG. 13 is a path connection sequence diagram when soft handover occursin the arrangement shown in FIG. 12;

FIG. 14 is a view showing the arrangement of FIG. 4 in accordance withan open RAN architecture;

FIG. 15 is a view for explaining the problem of Node B replacement inthe network shown in FIG. 5;

FIG. 16 is a view showing the network configuration of an embodiment ofthe present invention;

FIG. 17 is a sequence diagram showing the operation of the embodiment ofthe present invention;

FIG. 18 is a functional block diagram of a monitor controller;

FIG. 19 is a flowchart showing an example of the operation of themonitor controller;

FIG. 20 is a view showing an example of the contents of a database;

FIG. 21 is a flowchart showing the operation of a Node B;

FIG. 22 is a flowchart showing the operation of a CPE;

FIG. 23 is a view showing the network configuration of anotherembodiment of the present invention;

FIG. 24 is a sequence diagram showing the operation of the otherembodiment of the present invention;

FIG. 25 is a flowchart showing another example of the operation of themonitor controller;

FIG. 26 is a view showing another example of the contents of thedatabase;

FIG. 27 is a flowchart showing the operation of a base station resourcecontrol unit; and

FIG. 28 is a flowchart showing the operation of a terminal resourcecontrol unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several preferred embodiments of the present invention will be describedin detail below with reference to the accompanying drawings.

First, FIG. 4 is a functional block diagram as a premise of the presentinvention, in which the same reference numerals as in FIG. 2 denote thesame parts. As shown in FIG. 4, an RNC 4 is separated into a C planecontroller (CPE: Control Plane Equipment) 41 which corresponds to a Cplane for controlling signaling, and a U plane controller (UPE: UserPlane Equipment) 42 which corresponds to a U plane for controlling userdata.

All signaling operations are directly performed between devices and acentral controller (CP: Control Processor) 16 installed in the C planecontroller 41. However, RRC signaling between a mobile terminal unit(UE) 2 and the RNC 4 is transferred to an RRC 15 in the C planecontroller 41 after an RLC 131 or 132 is terminated in the U planecontroller 42, since the C plane and U plane cannot be clearlyseparated.

With this arrangement, in the existing RNC protocol layer architectureshown in FIG. 2, a physical layer (PHY) 11 indicated by L1 can beseparated into a Node B (radio base station) 6, data link layers 12 to14 indicated by L2 can be separated into the U plane controller 42, anda network layer 15 indicated by L3 and its upper layers can be separatedinto the C plane controller 41.

The RRC 15 in the C plane controller 41 controls individual deviceswhich terminate the physical layer 11 in the Node B, and the MAC layer12, RLC layer 13, and BMC layer 14 in the U plane controller 42, byusing C-SAPs (Control Service Access Points) which provide controlchannels. Also, the CP 16 in the C plane controller 41 directlyterminates and processes a signaling NBAP between the Node B 6 and RNC4, a signaling RNSAP between the RNC 4 and a C plane controller (CPE) 43in another RNC, and a signaling RANAP between the RNC 4 and an MSC(Mobile Switching Center) 31 or an SGSN (Serving GPRS (Global PacketRadio Service) Switching Node) 32.

Note that the MSC 31 has a channel switching function, the SGSN 32 has apacket switching function, and both of which are included in a corenetwork (CN) 3 shown in FIG. 1.

Also, RRC signaling used between the RNC 4 and mobile terminal unit 2 isterminated by the RRC layer 15 in the C plane controller 41 via themobile terminal unit 2, the Node B 6, and the MAC layer 12 and RLC layer13 in the U plane controller 42. PCH/FACH is terminated by a MAC-c/shlayer 121 and the RLC layer 13 in the U plane controller 42 andtransmitted to the C plane controller 41, since the relationship betweenthe Node B 6 and U plane controller 42 is always fixed after the LogicalO & M protocol (which is physically signaling by which the RN controlsthe resources installed in the Node B, and is defined in thespecification (25.401) of 3GPP), and is not changed unless station datais changed.

A DCH (Dedicated Channel) for transmitting user data can connect anarbitrary Node B and the U plane controller 42. After path selection andsynthesis are performed between a plurality of Node Bs by aselector/synthesizer 123 in the U plane controller 42, the DCH isterminated by a MAC-d layer 122 and the RLC layer 13, and transmitted tothe MSC 31 having a channel switching function or the SGSN 32 having apacket switching function via the C plane controller 41. Note that whensoft handover occurs, the selector/synthesizer 123 selects andsynthesizes DCHs from a plurality of Node Bs, selects a channel havingthe highest quality (reception quality) from these Node Bs, and sendsthe selected channel to the host apparatus.

By the use of the apparatus configuration shown in FIG. 4 as describedabove, a system configuration having high scalability can be assembled.That is, to increase the signaling throughput, the C plane controller 41alone can be added, and, to increase the user data transfer rate, theuser plane controller 42 alone can be added. Also, the individualdevices in the U plane controller 42 have no relationship with eachother and are controlled by the RRC 15 in the C plane controller 41.Therefore, these devices may also be installed as independent devices.

FIG. 5 is a view for explaining that the scalability can be ensuredbetween the C plane controller (CPE) 41 and U plane controller (UPE) 42separated on the basis of the principle shown in FIG. 4. C planecontrollers 41 a to 41 c and U plane controllers 42 a to 42 c areconnected via a device 17 such as an IP router or hub. Conventionally, aC plane controller and U plane controller are integrated into a singleRNC device, so they can be added only in the form of an RNC. However, aC plane controller performs a signaling process such as a callingprocess, so the throughput may become insufficient if the amount ofcalls increases. In this case, the processing can be easily dispersed byadding a new C plane controller.

For example, an algorithm which determines that when there are two Cplane controllers 41 a and 41 b, the C plane controller 41 a is used ifthe lowermost digit of the terminal number of the mobile terminal unit 2is an even number, and the C plane controller 41 b is used if it is anodd number, is changed such that when there are three C planecontrollers 41 a to 41 c, the C plane controller 41 a is used if thelowermost digit of the terminal number is 0, 1, 2, or 3, the C planecontroller 41 b is used if it is 4, 5, or 6, and the C plane controller41 c is used if it is 7, 8, or 9. In this manner, the throughput can beincreased by about 1.5 times.

Separately, a U plane controller transfers user data, so the throughputmay become insufficient if the transmission/reception data amount to betransferred by each mobile terminal unit increases. In this case, theprocessing can be easily dispersed by adding a new U plane controller.For example, an arrangement in which Node Bs 6 a to 6 f are connectedthree by three to two U plane controllers 42 a and 42 b is changed to anarrangement in which Node Bs 6 a to 6 f are connected two by two tothree U plane controllers 41 a to 42 c. In this way, the transfer ratecan be readily increased by about 1.5 times.

Furthermore, if the UPE 42 a has failed, the replacement of a Node Bunder the control of this UPE can be easily switched to another normalUPE.

FIG. 6 is a view showing the state in which the mobile terminal unit UE2 is performing soft handover between the Node Bs 6 a and 6 b. DCHs areconnected from both the Node Bs 6 a and 6 b to the terminal 2. Byselection and synthesis by the selector/synthesizer 123 in the U planecontroller 42 a, a channel having higher channel quality is selectedfrom the Node Bs 6 a and 6 b and transmitted to the host apparatus.

FIG. 7 shows a sequence in which the mobile terminal unit UE performsvoice communication by using a Node B #1 (6 a) and U plane controller(UPE) #1 (42 a) (step S1), requests a Node B #2 (6 b) for soft handover,and connects a path between the terminal UE and Node B #2. A C planecontroller (CPE) #1 (41 a) manages the resources of a U plane controller#1 and the Node B #1, and a C plane controller #2 (41 b) manages theresources of the U plane controller #2 (42 b) and Node B #2.

The soft handover request is notified, as “MEASUREMENT REPORT (RRC)”,from the terminal UE to the C plane controller #1 via the Node B #1 andU plane controller #1 (step S2). The C plane controller #1 acquires anIP address for soft handover with respect to the U plane controller #1,and notifies the U plan controller #1 of the IP address together with“RADIO LINK SETUP REQUEST” (step S3). The U plane controller #1 respondsto the C plane controller #1 by “RADIO LINK SETUP RESPONSE” (step S4).

Then, the C plane controller #1 transmits, to the C plane controller #2which manages the Node B #2 as the transfer destination, “RADIO LINKSETUP REQUEST (RNSAP)” and the IP address, which is acquired for softhandover, of the U plane controller #1 (step S5), and the C planecontroller #2 transmits, to the Node B #2, “RADIO LINK SETUP REQUEST(NBAP)” and the IP address, which is acquired for soft handover, of theU plane controller #1 (step S6).

When notifying the C plane controller #2 of “RADIO LINK SETUP RESPONSE(NBAP)”, the Node B #2 also notifies its IP address (step S7). Then, theC plane controller #2 notifies the C plane controller #1 of “RADIO LINKSETUP RESPONSE (RNSAP)” together with the IP address of the Node B #2(step S8). The C plane controller #1 notifies the U plane controller #1of the IP address of the Node B #2 by “RADIO LINK SETUP INDICATION”(step S9).

By the above procedures, the U plane controller #1 is notified of the IPaddress of the Node B #2, and the Node B #2 is notified of the IPaddress of the U plane controller #1, so user data can be transmittedand received. At the same time, the C plane controller #1 notifies theterminal UE of “ACTIVE SET UPDATE (RRC)” (step S10). When the terminalUE notifies the C plane controller #1 of “ACTIVE SET UPDATE COMPLETE(RRC)” (step S11), radio synchronization is started between the terminalUE and Node B #2 (step S12).

After layer 1 (L1) synchronization of the radio channel between theterminal UE and Node B #2 is completed, the Node B #2 notifies the Cplane controller #2 of “RADIO LINK RESPONSE INDICATION (NBAP)” (stepS13). The C plane controller #2 transmits “RADIO LINK RESTORE INDICATION(RNSAP)” to the C plane controller #1 (step S14), the setting of thepath between the terminal UE and Node B #2 is completed, and the softhandover path connecting to the U plane controller #1 via the Node Bs #1and #2 is set (step S15).

In the present invention as described above, soft handover across RNCscan be performed by connecting a path from a single U plane controllerto a plurality of Node Bs, without setting any path between the driftRNC and serving RNC in relation to user data unlike in the conventionalsystems. Therefore, the same U plane controller can be kept used, nopaths between the RNCs are necessary, the resources can be effectivelyused, and a delay caused by transferring data via the RNCs can beprevented.

A modification in which an RNC is separated into a C plane controllerand U plane controller, and the U plane controller is incorporated intoa Node B is also possible. In this modification, if the U planecontroller incorporated into the Node B does not have the function (theselector/synthesizer 123 shown in FIG. 4) of executing selection andsynthesis of user data, no soft handover can be executed via a pluralityof Node Bs. This is equivalent to discarding the merits of the use ofCDMA in a radio section. It is, therefore, possible to give each Node Ba function of selecting and synthesizing user data, and performcommunication between the Node Bs.

FIG. 8 shows a network configuration in which an RNC is separated into aC plane controller 42 and U plane controller 41, and U plane controllers42 a to 42 c are incorporated into Node Bs 6 a to 6 c, respectively. TheNode Bs 6 a to 6 c, the C plane controller 41, and a CN 3 are connectedacross an IP network 100.

A method of executing handover including a plurality of Node Bs in theIP network shown in FIG. 8 will be explained below. Assume that the Cplane controller 41 knows the IP address of each Node B.

FIG. 9 shows an example in which a radio link (RL) is set via two NodeBs from the state in which a terminal UE has no radio link (RL). From aplurality of Node Bs (in FIG. 9, a Node B #1 and Node B #2), the C planecontroller (CPE) selects a Node B as a serving node (in FIG. 9, the NodeB #1) (step S20) . The C plane controller notifies a Node B of the IPaddress of the serving Node B (in FIG. 9, the Node B #1) and the IPaddress of the other Node B (in FIG. 9, the Node B #2) by a “Radio LinkSetup Request” message, such that these two IP addresses can bedistinguished from each other (steps S21 and S22).

The C plane controller designates a Node B which controls a cell havingthe highest quality as a serving Node B. The Node B compares its own IPaddress with the IP address of the serving Node B, and, if its own IPaddress and the IP address of the serving Node B are equal, recognizesthat the Node B itself is the serving Node B (step S22). The other NodeBs recognize the IP address of the serving Node B as the transferdestination of UL (UpLink) data (step S24).

When assuring resources necessary to set a radio link, each Node Breturns a “Radio Link Setup Response” message to the C plane controller(steps S25 and S26). After that, U plane synchronization is established(step S27).

In the case of DL (DownLink) data transfer (step S28), the serving NodeB transfers data to the IP address of the other Node B notified by the“Radio Link Setup Request” message (step S29). In the case of UL(UpLink) data transfer, the serving Node B compares data received fromthe individual Node Bs, and transfers data having the highest quality tothe host (step S30).

FIG. 10 shows an example in which soft handover occurs when a radio linkis added via a new Node B from the state in which a mobile terminal unitalready has a radio link. In this case, it is necessary to notify a NodeB (in FIG. 10, a Node B #2) of the IP address of a serving Node B andthe IP address of a Node B included in soft handover (step S31).

First, therefore, a radio link is set for a new Node B (in FIG. 10, aNode B #1) by using “Radio Link Setup Request” message (step S32) and“Radio Link Setup Response” message (step S33). After that, all Node Bsincluded in soft handover are notified of the IP address of the servingNode B and the IP address of the Node B included in soft handover.

As a means for the purpose, a “Soft Handover Indication” message isnewly proposed (steps S36 and S37). This message contains the IP addressof the serving Node B and the IP address of the Node B included in softhandover. The operation after that is the same as in FIG. 9, andindicated by the same reference numerals as in FIG. 9.

FIGS. 9 and 10 each show soft handover including two Node Bs as anexample. However, the above mechanism is applicable to a case in whichtwo or more Node Bs are included in soft handover. In this case, aplurality of IP addresses are set in “Other Node B IP address” in stepsS36 and S37 of FIGS. 9 and 10.

FIG. 11 is a view showing an example in which the overall function ofthe open RAN architecture shown in FIG. 3 is divided into two controlfunctions. With reference to FIG. 11, this example comprises a terminalposition detector 101 which collects and calculates the positions ofterminals, a common radio resource manager 102 which manages the radioaccess network environment and optimizes the network load, apaging/broadcast network element 103 which controls the flows of radiobroadcast/multicast and notifies the states of radiobroadcast/multicast, a cell controller 104 which controls permission,congestion, and allocation of radio access to each radio base stationapparatus, a mobile controller 105 which establishes and releases atransmission channel, a cell transmission gateway 107 which transmitsindividual radio channel signals and perform multiplexing/separation ofa common radio channel signal, a user radio gateway 108 which encryptsand decrypts a radio channel and controls compression,multiplexing/separation, and retransmission of a header, and a radiolayer 106 which generates position information of a terminal, encodesand decodes a radio channel, or controls the electric power of a radiochannel. These components are the same as shown in FIG. 3.

In this example, a terminal resource control unit 110 as a first controlmeans is formed by the components for controlling the terminalresources, i.e., the terminal position detector 101, common radioresource manager 102, paging/broadcast network 103, and mobilecontroller 105. Also, a base station resource control unit 120 as asecond control means is formed by the components for controlling thebase station resources, i.e., the radio layer 106, cell transmissiongateway 107, and user radio gateway 108.

By the use of the apparatus configuration described above, a systemconfiguration having high scalability can be assembled. Namely, toincrease the signaling throughput, the terminal resource control unit110 alone can be added, and, to increase the user data transfer rate,the base station resource control unit 120 alone can be added.

Also, since all the radio specific control portions are formed in thebase station resource control unit 120, it is no longer necessary toexchange large amounts of signals between devices even when the U planecontrol function and C plane control function are separated.Furthermore, when this configuration is applied to mobile communicationsystems having different radio schemes, it is only necessary to preparebase station resource control units 120 which are equal in number to theradio schemes, and each of which performs control matching thecorresponding radio scheme. Since all the base station resource controlunits 120 are controlled together by the terminal resource control unit110, multiple areas can be controlled by a small scale.

FIG. 12 is a view for explaining the ability to ensure the scalabilitybetween the terminal resource control unit 110 and base station resourcecontrol unit 120 shown in FIG. 11. Terminal resource control units 110 ato 110 c and base station resource control units 120 a to 120 c areconnected via a device 17 such as an IP router or hub. Conventionally,the terminal resource control unit 110 and base station resource controlunit 120 are integrated into a single RNC device, so they can be addedonly in the form of an RNC. However, the terminal resource control unit110 performs a signaling process such as a calling process, so thethroughput may become insufficient if the amount of calls increases. Inthis case, the processing can be easily dispersed by adding a newterminal resource control unit 110. An example is the same as explainedwith reference to FIG. 5.

FIG. 13 shows a sequence in which, in the mobile communication systemshown in FIGS. 11 and 12, a mobile terminal unit UE performs voicecommunication by using a Node B #1 (6 a) and base station resourcecontrol unit #1 (120 a) (step S1), requests a Node B #2 (6 b) for softhandover, and connects a path between the terminal UE and Node B #2.Note that FIG. 13 corresponds to the sequence shown in FIG. 7, and thesame reference numerals denote the same steps.

A terminal resource control unit #1 (110 a) manages the resources of thebase station resource control unit #1 and Node B #1, and a terminalresource control unit #2 (110 b) manages the resources of a base stationresource control unit #2 (120 b) and the Node B #2. The soft handoverrequest is notified, as “MEASUREMENT REPORT (RRC)”, from the terminal UEto the terminal resource control unit #1 via the Node B #1 and basestation resource control unit #1 (step S2).

The terminal resource control unit #1 acquires an IP address for softhandover with respect to the base station resource control unit #1, and,on the basis of megacop (IETF RFC3015), notifies the base stationresource control unit #1 of the IP address together with “RADIO LINKSETUP REQUEST” (step S3). On the basis of megacop (IETF RFC3015), thebase station resource control unit #1 responds to the terminal resourcecontrol unit #1 by “RADIO LINK SETUP RESPONSE” (step S4).

Then, the terminal resource control unit #1 transmits, to the terminalresource control unit #2 which manages the Node B #2 as the transferdestination, “RADIO LINK SETUP REQUEST (RNSAP)” and the IP address,which is acquired for soft handover, of the base station resourcecontrol unit #1 (step S5), and the terminal resource control unit #2transmits, to the Node B #2 via the base station resource control unit#2, “RADIO LINK SETUP REQUEST (NBAP)” and the IP address, which isacquired for soft handover, of the base station resource control unit #1(steps S6 and S6′).

When notifying the terminal resource control unit #2 of “RADIO LINKSETUP RESPONSE (NBAP)”, the Node B #2 notifies its IP address via thebase station resource control unit #2 (steps S7 and S7′). Then, theterminal resource control unit #2 notifies the terminal resource controlunit #1 of “RADIO LINK SETUP RESPONSE (RNSAP)” together with the IPaddress of the Node B #2 (step S8).

The terminal resource control unit #1 notifies the base station resourcecontrol unit #1 of the IP address of the Node B #2 by “RADIO LINK SETUPINDICATION” (step S9). By these means, the base station resource controlunit #1 is notified of the IP address of the Node B #2, and the Node B#2 is notified of the IP address of the base station resource controlunit #1, so user data can be transmitted and received. At the same time,the terminal resource control unit #1 notifies the terminal UE of“ACTIVE SET UPDATE (RRC)” (step S10).

When the terminal UE notifies the terminal resource control unit #1 of“ACTIVE SET UPDATE COMPLETE (RRC)” (step S11), radio synchronization isstarted between the terminal UE and Node B #2 (step S12).

After layer 1 (L1) synchronization of the radio channel between theterminal UE and Node B #2 is completed, the Node B #2 notifies theterminal resource control unit #2 of “RADIO LINK RESPONSE INDICATION(NBAP)” via the base station resource control unit #2 (steps S13 andS13).

The terminal resource control unit #2 transmits “RADIO LINK RESTOREINDICATION (RNSAP)” to the terminal resource control unit #1 (step S14),the setting of the path between the terminal UE and Node B #2 iscompleted, and the soft handover path connecting to the base stationresource control unit #1 via the Node Bs #1 and #2 is set (step S15).

In the present invention as described above, soft handover across RNCscan be performed by connecting a path from a single base stationresource control unit to a plurality of Node Bs, without setting anypath between the drift RNC and serving RNC in relation to user dataunlike in the conventional systems. Therefore, the same base stationresource control unit can be kept used, no paths between the RNCs arenecessary, the resources can be effectively used, and a delay caused bytransferring data via the RNCs can be prevented.

A modification in which an RNC is separated into a terminal resourcecontrol unit and base station resource control unit, and the basestation resource control unit is incorporated into a Node B is alsopossible. In this modification, if the base station resource controlunit incorporated into the Node B does not have the function ofexecuting selection and synthesis of user data, no soft handover can beexecuted via a plurality of Node Bs. This is equivalent to discardingthe merits of the use of CDMA in a radio section. It is, therefore,possible to give each Node B a function of selecting and synthesizinguser data, and perform communication between Node Bs.

Note that in FIGS. 8 to 10, similar functional operations can beperformed by replacing the CPE with the terminal resource control unitand the UPE with the base station resource control unit.

FIG. 14 is a functional block diagram when the arrangement in which theRAN is separated into the CPE 41 and UPE 42 by using a protocolarchitecture form is rewritten by using an open RAN architecture form.The same reference numerals as in FIG. 11 denote the same parts in FIG.14. That is, a cell controller 104 which is the element which forms theterminal resource control unit 110 in FIG. 11 is an element which formsa CPE in FIG. 14, and a radio layer 106, cell transmission gateway 107,and user radio gateway 108 form a UPE 42.

As described above, as shown in FIG. 4 or 11, when the RAN is physicallyseparated into the CPE 41 and UPE 42, or into the terminal resourcecontrol unit 110 and base station resource control unit 120, Node Breplacement can be easily performed as shown in FIG. 5 or 12. In thiscase, as shown in FIG. 5 or 12, if a plurality of CPEs or terminalresource control units exist, one of these devices must representativelycontrol Node B replacement.

That is, as shown in FIG. 15, for example, in a system in which aplurality of CPEs (41 a to 41 c) exist, an OMC (Operating andMaintenance Center) 50 having functions of, e.g., displaying the stateof each device and setting the state of each device by allowing anoperator to input commands can be connected to the CPE 41 a. In thiscase, however, the CPE 41 a must have a function of controlling Node Breplacement under the control of the OMC 50, in addition to functions ofthe CPEs 41 b and 41 c. Consequently, all the CPEs cannot be given thesame function, so the efficiency is low in both cost and manufacture.This problem also arises in the system having a plurality of terminalresource control units as shown in FIG. 12.

In the present invention, therefore, as indicated by an embodiment shownin FIG. 16, all of a plurality of CPEs can be given the same function.Also, as indicated by another embodiment shown in FIG. 23, all of aplurality of terminal resource control units can be given the samefunction.

First, the embodiment shown in FIG. 16 will be explained below. Notethat the same reference numerals as in FIG. 5 denote the same parts inFIG. 16. Referring to FIG. 16, an OMC 50 is connected to a radio basestation replacement control apparatus (monitor controller) 51 having afunction of controlling Node B replacement. The monitor controller 51 isconnected to other devices via a router 17.

The monitor controller 51 is connected to a database 52 which stores therelationship between address information (an IP address which isidentification information unique to each Node B) of each Node B underthe control of each UPE, and cell information (cell address informationwhich is identification information unique to each cell) under thecontrol of each Node B. Note that although the database 52 isindependent of the monitor controller 51, the database 52 may, ofcourse, also be an internal memory of the monitor apparatus.

An operation sequence by which the monitor controller 51 manually orautomatically makes decisions and performs Node B replacement when, forexample, a UPE #1 has failed will be explained below with reference toFIG. 17. Assume that a Node B #1 is under the control of the UPE #1, anda Node B #2 is under the control of a UPE #2. If a failure is detectedin the UPE #1, the monitor controller is notified of the detection ofthe failure (step S121) . It is also possible, by assuming that the UPE#1 may become completely inoperable, to periodically transmit packetsfrom the monitor controller and determine that a failure has occurred ifno response is returned.

The monitor controller switches the control over the Node B from the UPE#1 to the UPE #2. This switching will be referred to as cell settingchange hereinafter. The monitor controller designates cell settingchange (switching of the control from the UPE #1 to the UPE #2) to theNode B #1 (step S122). This cell setting change designation containsaddress information, which indicates the change destination, of the UPE#2. The Node B #1 changes the setting so as to be placed under thecontrol of the UPE #2. Then, the Node B #1 returns a response indicatingcell setting change OK to the monitor controller (step S123).

In this network configuration, each CPE must have address information ofall UPEs and cell information of Node Bs under the control of the CPE.Accordingly, the monitor controller notifies a CPE #1 and CPE #2 of thecell information change (steps S124 and S126), and waits for an OKresponse (steps S125 and S127), thereby completing the Node Breplacement.

FIG. 18 is a functional block diagram of the monitor controller 51. Thisarrangement includes a database search unit 511 for searching a database51, a database rewriting unit 512 for rewriting the contents of thedatabase 511, a cell setting change designation unit 513 for generatinga cell setting change designation to a Node B, a cell setting changenotification unit 514 for notifying a CPE of cell setting change inresponse to the reception of cell setting change OK from a Node B, anexternal interface unit 515, a control unit (CPU) 516 for controllingthese units, and a recording medium 517 storing control sequences asprograms.

FIG. 19 is a flowchart showing the operation of the monitor controller.When receiving failure notification (step S121 in FIG. 17) from the UPE#1 (step S131), the monitor controller searches the database 52 for aNode B under the control of the UPE #1 (step S132). The contents of thedatabase 52 in this case are as shown in the upper half of FIG. 20. Thatis, the database 52 stores the correspondence of address information ofa Node B presently under the control of each UPE to address informationof a cell under the control of the Node B.

As a result of this search, the Node B #1 under the control of the UPE#1 in which the failure has occurred is found, the monitor controllergenerates and transmits a cell setting change designation to the Node B#1 so that the Node B #1 is placed under the control of the UPE #2 (stepS133). This cell setting change designation naturally contains addressinformation of the UPE #2 as the cell change destination. In this case,the control over the Node B is switched from the UPE in which thefailure has occurred to another UPE by various methods, e.g., a methodby which the control is switched to a UPE which is physically close andhas a light load, and the method is not particularly limited.

When receiving cell setting change OK from the Node B #1 (step S134),the monitor controller rewrites the database 52 as shown in the lowerhalf of FIG. 20 (step S35), and notifies the CPEs #1 and #2 of the cellsetting change, i.e., the address information of the Node B as an objectof the cell setting change and the address information of the UPE as thechange destination (step S136). When cell setting OK is returned fromeach CPE after that (step S137), the processing is terminated.

FIG. 21 is a flowchart showing the operation of the Node B #1. When thecell setting change designation is transmitted from the monitorcontroller (step S141), the Node B #1 changes the cell setting such thatthe Node B #1 presently under the control of the UPE #1 is placed underthe control of the UPE #2 (step S142) . This cell setting change meansthat the address information of the UPE having the control is changedfrom #1 to #2 in a memory 61. Then, the Node B #1 transmits, to themonitor controller, cell setting change OK indicating that the cellsetting change is completed (step S143).

FIG. 22 is a flowchart showing the operation of the CPE. When the cellsetting change notification is transmitted from the monitor controller(step S151), the CPE changes the cell setting on the basis ofinformation, contained in this notification, which indicates that thecontrol over the Node B #1 is switched from the UPE #1 to the UPE #2(step S152). This cell setting change means rewriting the information toindicate that the control over the Node B #1 is switched from the UPE #1to the UPE #2, in a memory 411. After that, the CPE transmits, to themonitor controller, cell setting OK indicating that the cell settingchange is completed (step S153).

FIG. 23 shows a system configuration related to another embodiment ofthe present invention, which corresponds to the system configurationshown in FIG. 12, and in which the same reference numerals as in FIG. 12denote the same parts. In this embodiment, an RNC is separated into aplurality of terminal resource control units and a plurality of basestation resource control units. The system includes a monitor controller51, and an OMC 50 is connected to the monitor controller 51 in thisembodiment as well. The monitor controller 51 is connected to otherdevices via a router 17.

An operation sequence by which the monitor controller 51 manually orautomatically makes decisions and performs Node B replacement when, forexample, a base station resource control unit #1 has failed will beexplained below with reference to FIG. 24. Assume that a Node B #1 isunder the control of the base station resource control unit #1, and aNode B #2 is under the control of a base station resource control unit#2.

If a failure is detected in the base station resource control unit #1,the monitor controller is notified of the detection of the failure (stepS161). It is also possible, by assuming that the base station resourcecontrol unit #1 may become completely inoperable, to periodicallytransmit packets from the monitor controller and determine that afailure has occurred if no response is returned.

The monitor controller switches the control over the Node B from thebase station resource control unit #1 to the base station resourcecontrol unit #2. This switching will be referred to as cell settingchange hereinafter. The monitor controller designates cell settingchange to the base station resource control unit #2 (step S162). Thiscell setting change designation contains address information of the NodeB #1 to be changed. The base station resource control unit #2 changesthe cell setting so that the Node B #1 is placed under the control ofthe base station resource control unit #2, and transmits a cell settingchange designation to the Node B #1 (step S163) This cell setting changedesignation contains address information, which indicates the changedestination, of the base station resource control unit #2.

The Node B #1 changes the setting so as to be placed under the controlof the base station resource control unit #2. Then, the Node B #1returns a response indicating cell setting change OK to the base stationresource control unit #2 (step S164). The base station resource controlunit #2 transmits a response indicating cell setting change OK to themonitor controller (step S165).

In this network configuration, each terminal resource control unit musthave address information of all base station resource control units andcell information of Node Bs under the control of the terminal resourcecontrol unit. Accordingly, the monitor controller notifies terminalresource control units #1 and #2 of the cell information change (stepsS166 and S168), and waits for an OK response (steps S167 and S169),thereby completing the Node B replacement.

The functional blocks of the monitor controller in this embodiment arethe same as shown in FIG. 18 of the above embodiment. FIG. 25 is aflowchart showing the operation of the monitor controller in thisembodiment. When receiving the failure notification (step S161 in FIG.24) from the base station resource control unit #1 (step S171), themonitor controller searches a database 52 for a Node B under the controlof the base station resource control unit #1 (step S172). The contentsof the database 52 in this case are as shown in the upper half of FIG.26. That is, the database 52 stores the correspondence of addressinformation of a Node B presently under the control of each base stationresource control unit to address information of a cell under the controlof the Node B.

As a result of this search, the Node B #1 under the control of the basestation resource control unit #1 in which the failure has occurred isfound, and the monitor controller generates and transmits a cell settingchange designation to the base station resource control unit #2 so thatthe Node B #1 is placed under the control of the base station resourcecontrol unit #2 (step S173) . This cell setting change designationnaturally contains address information of the Node B #2 as an object ofthe cell change. In this case, the control over the Node B is switchedfrom the base station resource control unit in which the failure hasoccurred to another base station resource control unit by variousmethods, e.g., a method by which the control is switched to a basestation resource control unit which is physically close and has a lightload, and the method is not particularly limited.

When receiving cell setting change OK from the base station resourcecontrol unit #2 (step S174), the monitor controller rewrites thedatabase 52 as shown in the lower half of FIG. 26 (step S175), andnotifies the terminal resource control units #1 and #2 of the cellsetting change, i.e., the address information of the Node B as an objectof the cell setting change and the address information of the basestation resource control unit as the change destination (step S176).When cell setting OK is returned from each terminal resource controlunit after that (step S177), the processing is terminated.

FIG. 27 is a flowchart showing the operation of the base stationresource control unit #2. When the cell setting change designation istransmitted from the monitor controller (step S181), the base stationresource control unit #2 changes the cell setting such that the controlover the Node B #1 is switched from the base station resource controlunit #1 to the base station resource control unit #2 (step S182). Thiscell setting change means that #1 is added to the address information ofthe Node B under the control, in a memory 121. Then, the base stationresource control unit #2 transmits a cell setting change designation tothe Node B #1 (step S183). When receiving cell setting change OKindicating that the cell setting change is completed from the Node B #1(step S184), the base station resource control unit #2 transmits cellsetting change OK to the monitor controller (step S185).

FIG. 28 is a flowchart showing the operation of the terminal resourcecontrol unit. When the cell setting change notification is transmittedfrom the monitor controller (step S191), the terminal resource controlunit changes the cell setting on the basis of information, contained inthis notification, which indicates that the control over the Node B #1is switched from the base station resource control unit #1 to the basestation resource control unit #2 (step S192). This cell setting changemeans rewriting the information to indicate that the control over theNode B #1 is switched from the base station resource control unit #1 tothe base station resource control unit #2, in a memory 111. After that,the terminal resource control unit transmits, to the monitor controller,cell setting OK indicating that the cell setting change is completed(step S193).

Note that in each embodiment described above, the monitor controller 51performs Node B replacement by using the failure notification or failuredetection from the UPE or base station resource control unit as atrigger. However, it is obviously also possible to perform Node Breplacement by using a command from the OMC 50, i.e., an instructionfrom the operator as a trigger.

Note also that the operation of each unit in each embodiment describedabove may also be performed by prestoring the operation sequence as aprogram in the recording medium, and allowing the CPU as a computer toread and execute the program.

1-18. (canceled)
 19. A mobile communication system, comprising: a mobileterminal unit in which a calling process and a Node b utilized for cellsetting are controlled by the same protocol architecture;; a radio basestation which communicates with said mobile terminal unit via a radiochannel; and a radio controller which controls said radio base station,and is physically separated into first control means for controllingtransfer of signaling and second control means for accommodating saidradio base station under the control and controlling transfer of userdata; and a radio base station replacement control apparatus whichcontrols replacement of said radio base station.
 20. A mobilecommunication system, comprising: a mobile terminal unit in which acalling process and a Node b utilized for cell setting are controlled bythe same protocol architecture; a radio base station which communicateswith said mobile terminal unit via a radio channel; and a radiocontroller which controls said radio base station, and is physicallyseparated into first control means for performing control independent ofa radio transmission scheme and second control means for accommodatingsaid radio base station under the control and performing controldepending on a radio transmission scheme; and a radio base stationreplacement control apparatus which controls replacement of said radiobase station.
 21. A mobile communication systems comprising: a mobileterminal unit in which a calling process and a Node b utilized for cellsetting are controlled by the same protocol architecture; a radio basestation which communicates with said mobile terminal unit via a radiochannel; and a radio controller which controls said radio base station;and is physically separated into first control means for controllingtransfer of signaling and second control means for accommodating saidradio base station under the control and controlling transfer of userdata, said second control means performing control depending on a radiotransmission scheme; and a radio base station replacement controlapparatus which controls replacement of said radio base station.
 22. Amobile communication system, comprising: a mobile terminal unit in whicha calling process and a Node b utilized for cell setting are controlledby the same protocol architecture; a radio base station whichcommunicates with said mobile terminal unit via a radio channel; and aradio controller which controls said radio base station, and isphysically separated into first control means for controlling a terminalresource of said mobile terminal unit and second control means foraccommodating said radio base station under the control and controllinga base station resource of said radio base station; and a radio basestation replacement control apparatus which controls replacement of saidradio base station.
 23. A mobile communication system according to claim19, further comprising a network which connects said first controlmeans, second control means, and radio base station replacement controlapparatus.
 24. A mobile communication system according to claim 19,wherein said radio base station replacement control apparatus comprisesmeans for notifying, in response to an external trigger, a radio basestation as an object of replacement of identification information ofsecond control means which is to newly accommodate said radio basestation.
 25. A mobile communication system according to claim 24,wherein said radio base station replacement control apparatus furthercomprises means for notifying said first control means of identificationinformation of said radio base station as an object of replacement andidentification information of said second control means as anaccommodation destination.
 26. A radio base station replacement controlapparatus which controls replacement of a radio base station in a mobilecommunication system which comprises a mobile terminal unit in which acalling process and a Node b utilized for cell setting are controlled bythe same protocol architecture, said radio base station whichcommunicates with said mobile terminal unit via a radio channel, and aradio controller which controls said radio base station, and isphysically separated into first control means for controlling transferof signaling and second control means for accommodating said radio basestation under the control and controlling transfer of user data, whereinsaid first and second control means are physically independent of eachother.
 27. A radio base station replacement control apparatus whichcontrols replacement of a radio base station in a mobile communicationsystem which comprises a mobile terminal unit in which a calling processand a Node b utilized for cell setting are controlled by the sameprotocol architecture, said radio base station which communicates withsaid mobile terminal unit via a radio channel, and a radio controllerwhich controls said radio base station, and is physically separated intofirst control means for performing control independent of a radiotransmission scheme and second control means for accommodating saidradio base station under the control and performing control depending ona radio transmission scheme, wherein said first and second control meansare physically independent of each other.
 28. A radio base stationreplacement control apparatus which controls replacement of a radio basestation in a mobile communication system which comprises a mobileterminal unit in which a calling process and a Node b utilized for cellsetting are controlled by the same protocol architecture, said radiobase station which communicates with said mobile terminal unit via aradio channel, and a radio controller which controls said radio basestation, and is physically separated into first control means forcontrolling transfer of signaling and second control means foraccommodating said radio base station under the control and controllingtransfer of user data, said second control means performing controldepending on a radio transmission scheme, wherein said first and secondcontrol means are physically independent of each other.
 29. A radio basestation replacement control apparatus which controls replacement of aradio base station in a mobile communication system, which comprises amobile terminal unit in which a calling process and a Node b utilizedfor cell setting are controlled by the same protocol architecture, saidradio base station which communicates with said mobile terminal unit viaa radio channel, and a radio controller which controls said radio basestation, and is physically separated into first control means forcontrolling a terminal resource of said mobile terminal unit and secondcontrol means for accommodating said radio base station under thecontrol and controlling a base station resource of said radio basestation, wherein said first and second control means are physicallyindependent of each other.
 30. A radio base station replacement controlapparatus according to claim 26, wherein said first and second controlmeans are connected across a network.
 31. A radio base stationreplacement control apparatus according to claim 26, further comprisingmeans for notifying, in response to an external trigger, a radio basestation as an object of replacement of identification information ofsecond control means which is to newly accommodate said radio basestation.
 32. A radio base station replacement control apparatusaccording to claim 31, further comprising means for notifying said firstcontrol means of identification information of said radio base stationas an object of replacement and identification information of saidsecond control means as an accommodation destination.
 33. A radio basestation replacement control method in a communication system whichcomprises a mobile terminal unit in which a calling process and a Node butilized for cell setting are controlled by the same protocolarchitecture, a radio base station which communicates with the mobileterminal unit via a radio channel, a radio controller which controls theradio base station, and is physically separated into first control meansfor controlling transfer of signaling and second control means foraccommodating the radio base station under the control and controllingtransfer of user data, and a radio base station replacement controlapparatus which is provided physically independently of the first andsecond control means and controls replacement of the radio base station,wherein the method comprises the step of notifying, in response to anexternal trigger, a radio base station as an object of replacement ofidentification information of second control means which is to newlyaccommodate the radio base station.
 34. A radio base station replacementcontrol method according to claim 33, further comprising the step ofnotifying the first control means of identification information of theradio base station as an object of replacement and identificationinformation of the second control means as an accommodation destination.35. A program for causing a computer to execute a radio base stationreplacement control method in a communication system which comprises amobile terminal unit in which a calling process and a Node b utilizedfor cell setting are controlled by the same protocol architecture, aradio base station which communicates with the mobile terminal unit viaa radio channel, a radio controller which controls the radio basestation, and is physically separated into first control means forcontrolling transfer of signaling and second control means foraccommodating the radio base station under the control and controllingtransfer of user data, and a radio base station replacement controlapparatus which is provided physically independently of the first andsecond control means and controls replacement of the radio base station,wherein the program comprises the step of notifying, in response to anexternal trigger, a radio base station as an object of replacement ofidentification information of second control means which is to newlyaccommodate the radio base station.
 36. A program according to claim 35,further comprising the step of notifying the first control means ofidentification information of the radio base station as an object ofreplacement and identification information of the second control meansas an accommodation destination.
 37. A mobile communication systemaccording to claim 20, further comprising a network which connects saidfirst control means, second control means, and radio base stationreplacement control apparatus.
 38. A mobile communication systemaccording to claim 21, further comprising a network which connects saidfirst control means, second control means, and radio base stationreplacement control apparatus.
 39. A mobile communication systemaccording to claim 22, further comprising a network which connects saidfirst control means, second control means, and radio base stationreplacement control apparatus.
 40. A mobile communication systemaccording to claim 20, wherein said radio base station replacementcontrol apparatus comprises means for notifying, in response to anexternal trigger, a radio base station as an object of replacement ofidentification information of second control means which is to newlyaccommodate said radio base station.
 41. A mobile communication systemaccording to claim 21, wherein said radio base station replacementcontrol apparatus comprises means for notifying, in response to anexternal trigger, a radio base station as an object of replacement ofidentification information of second control means which is to newlyaccommodate said radio base station.
 42. A mobile communication systemaccording to claim 22, wherein said radio base station replacementcontrol apparatus comprises means for notifying, in response to anexternal trigger, a radio base station as an object of replacement ofidentification information of second control means which is to newlyaccommodate said radio base station.
 43. A mobile communication systemaccording to claim 23, wherein said radio base station replacementcontrol apparatus comprises means for notifying, in response to anexternal trigger, a radio base station as an object of replacement ofidentification information of second control means which is to newlyaccommodate said radio base station.
 44. A radio base stationreplacement control apparatus according to claim 27, wherein said firstand second control means are connected across a network.
 45. A radiobase station replacement control apparatus according to claim 28,wherein said first and second control means are connected across anetwork.
 46. A radio base station replacement control apparatusaccording to claim 29, wherein said first and second control means areconnected across a network.
 47. A radio base station replacement controlapparatus according to claim 27, further comprising means for notifying,in response to an external trigger, a radio base station as an object ofreplacement of identification information of second control means whichis to newly accommodate said radio base station.
 48. A radio basestation replacement control apparatus according to claim 28, furthercomprising means for notifying, in response to an external trigger, aradio base station as an object of replacement of identificationinformation of second control means which is to newly accommodate saidradio base station.
 49. A radio base station replacement controlapparatus according to claim 29, further comprising means for notifying,in response to an external trigger, a radio base station as an object ofreplacement of identification information of second control means whichis to newly accommodate said radio base station.
 50. A radio basestation replacement control apparatus according to claim 30, furthercomprising means for notifying, in response to an external trigger, aradio base station as an object of replacement of identificationinformation of second control means which is to newly accommodate saidradio base station.